Background/Aims: Helicobacter pylori eradication may facilitate the healing of iatrogenic ulcer after endoscopic resection of gastric neoplasm. This study involved designing a randomized, double-blinded, placebo-controlled, multicenter trial, performed by the Korean College of Helicobacter and Upper Gastrointestinal Research and the Medical Research Collaboration Center, Seoul National University Hospital. Methods: We intend to enroll up to 232 patients H.-pylori-positive patients who have gastric adenoma or early gastric cancer after endoscopic resection. The enrolled patients are being randomly allocated to the H.-pylori-eradication-plus-proton-pump-inhibitor group or the placebo-plus-proton-pump-inhibitor group based on their histology results and the size of the resected specimen. After random allocation, the iatrogenic ulcer size and stage are evaluated at 4- and 8-week follow-ups (with a window of ±7 days). The primary end point is the healing rate of the ulcer by stage, and the secondary end point is the rate of ulcer size reduction, relief rate from ulcer-related symptoms, and adverse-event rates. Results: More than 90% of the target subjects have already been enrolled into the study and are receiving ongoing periodic monitoring by the Medical Research Collaboration Center. Conclusions: Completion of the study should reveal whether H. pylori eradication can facilitate the healing of ulcer after endoscopic resection in Korea. (Gut Liver 2010;4:514-517)